Mr. Barr was aware of a federal investigation into the president-elect’s son for a year, but worked to keep him calm during the election, according to Wall Street Journal.

Mr. Trump has made Hunter Biden’s foreign business dealings a central theme in his campaign for re-election in an effort to discredit his opponent in the White House.

It now appears that the outgoing president is angry that Barr has not politicized the investigation and allowed Trump to use it to his advantage.

Trump took to Twitter on Saturday to shoot a bar.

He was responding to a tweet from a supporter who wrote that if Mr. Bar had “kept it silent” then “he should be fired by the end of work today.”

“A big disappointment!” Trump responded to a tweet from conservative broadcaster Todd Starnes.

Mr Trump went on to claim that once Mr Biden arrives at the White House, he will make sure that the investigation into his son is canceled.

“Why didn’t Bill Barr reveal the truth to the public, before the election, about Hunter Biden. Joe was lying on the debate stage that there was nothing wrong or still going on – the press confirmed. A big shame for Republicans at the polls!” He tweeted.

Trump added, “If Biden enters, nothing will happen to Hunter or Joe.”

“Barr will do nothing, and the next batch of party killers will quickly kill everything. Same thing with Durham.

“We caught them cold, espionage, betrayal and more (the hard part), but ‘justice’ took too long. It’ll be DOA! ”

Trump refused to concede his electoral defeat to Biden, and on Friday, the Supreme Court unanimously refused to file a controversial election case filed by a Texas attorney general.

Ken Paxton had wanted the nation’s highest court to nullify election results in the four states a major battlefield that helped secure Biden’s victory.

By rejecting the case, observers said, the Supreme Court has ruled out Trump’s last hope of defeating Biden in the courtroom after losing the ballot box.

But that does not appear to have dampened Mr. Trump’s confidence.

“We have started fighting !!!” The President tweeted after his attack on Mr. Bar.

Mr. Trump alleged widespread fraud in the election – in states he did not win – but the final results in the states that were the battlefield have now been approved by officials.

His legal team suffered a crushing series of defeats in courtrooms across the country in their attempt to keep Mr. Trump in power.

They failed to provide the judges with any evidence of vote fraud.